CPU Intermittently Pegs at 100% for 30-60 minutes. Tech Support

CPU Intermittently Pegs at 100% for 30-60 minutes.

Firstly I'd like to say that I'm more than tech-savvy but that after spending 4 months trying to fix the issue on my own I've given up. 

My issue is that 2-3 times a day, for between 30-60 minutes, the CPU in my machine simply ramps up to 100% (See:
http://imgur.com/MwCyq) and will sit with all 4 cores running at 100% for the better part of an hour before it returns to normal.
This occurs even when the machine is idling with no programs running and it
returns quickly if the machine is restarted during one of these "fits".
I have scanned for viruses (including in safe mode) hundreds of times using up to date versions of Malwarebytes Anti-Malware, Symantec and Spybot S&D with no success which leads me to
discount the idea that this is a Virus.
Furthermore I have flashed to the most recent version of the BIOS and I have also determined through driver testing that it is not an issue with the GPU.
I did a clean install of Windows 2 weeks ago which did not solve
the problem and hardware diagnostics do not indicate any physical issues with the machine. 

My System Specs are as follows:

HP Elitebook 8540w
Win 7 Professional
i5 M520 @ 2.4GHZ
BIOS - Current
Ram - 4GB
NVIDIA 880M

I have been working with a friend of mine who's professional IT on this and everything we have tried (detailed above) has failed.
This issue has been persisting since just after Christmas 2010 and my immense patience is beginning to wear thin.
I have searched
far and wide on the net to an answer to this problem which many people seem to have but there is no consensus on just what the cause of it is and all of the solutions which solved other problems have failed to work for me.
Thus I am appealing to the vast knowledge
of the Windows Answers community to see if they can shed some light on the issue. 

Thank You.

Solutions to the Problem CPU Intermittently Pegs at 100% for 30-60 minutes.

Download SmartPCFixer to Fix It (Free)

Do a "Clean Boot" - How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7
http://support.microsoft.com/kb/929135
(Perform Steps #1a, 1b, 1c, 1d and 1e)
Perform a clean startup to determine whether background programs are interfering with your game or program
http://support.microsoft.com/kb/331796

J W Stuart: http://www.pagestart.com

Note: It is recommended that you back up your files and folders before attempting this step:

• Move the mouse cursor over to the upper right side of the screen.
• A menu will pop up on the left. Click on the "Settings" feature on the menu.
• On the Settings window, click on the "Change PC settings."
• Now, left click on the "Update and recovery" feature.
• For the next step, left click on the "Recovery" feature.
• There is an option here saying "Refresh your PC without affecting your files." There, left click on the "Get started" button.
• Now, follow the instructions on the screen to finish the Refresh process.
• After the Refresh process has finished restart your Windows 8.1 or Windows 8 device.
• Check again to see if the error CPU Intermittently Pegs at 100% for 30-60 minutes. has been fixed.

If you do not possess the technical expertise required to accomplish this yourself or do not feel comfortable doing so, download and install a powerful automated tool to get the job done.

Recommended Method to Fix the Problem: CPU Intermittently Pegs at 100% for 30-60 minutes.:

How to Fix CPU Intermittently Pegs at 100% for 30-60 minutes. with SmartPCFixer?

1. Click the button to download SmartPCFixer . Install it on your system.  Open it, and it will perform a scan for your system. The junk files will be shown in the scan result.

2. After the scan is done, you can see the errors and problems which need to be fixed.

3. The Repair part is done, the speed of your computer will be much higher than before and the errors have been fixed. You can also use other functions in this software. Like dll downloading, windows updating and print spooler error repair.

Related: How Can You Update & Download NVidia 6100, 6800 GS/XT Display Driver v.260.89 WHQL,Where to Download NVidia GeForce 8800 GT WHQL-certified driver v.196.21,How to Update & Download NVidia GeForce Go 7400 Display Driver v.260.19.12,[Solved] Download NVidia GeForce GTX 460M Driver v.331.82,Download NVidia Quadro Plex Model IV VGA Driver v.304.43 Certified,Way to Download RealTek RTL8100C(L) Driver v.5.01,Way to Download RealTek RTL8100E Drivers v.694,Way to Update & Download RealTek RTL8101L Auto Installation Program v.6.110 driver,Method to Update & Download RealTek RTL8111G PXE and RPL ROM code v.2.58 driver,How to Update & Download RealTek RTL8411B(N) Driver v.10.003,Best Way to Update & Download ASUS A53SV nVidia Graphics Driver v.8.17.12.6686,Method to Herunterladen ASUS K75VJ Intel Rapid Storage Technology Treiber v.11.6.0.1030,How Can You Update & Download ASUS CG8580 Intel Chipset Driver v.9.3.0.1019,Method to Update & Download ASUS K41VD Intel INF Update Driver v.9.1.1.1015,Way to Update & Download ASUS Pro70T NB Probe v.3.0.0026 driver
Read More: [Solved] Control panel not responsive,How to Fix - Control Panel\All Control Panel Items\Personalisation?,Fast Solution to Problem: Contour Chart Legend Entry Fill Unchangeable,How Can I Fix - Convert Text to hyperlinked email address?,Troubleshoot:Continual blue screens and crashes (Win 7 x64); memory related?,Closing Internet Explorer causes error,Compare 2 Tables and Calculate the PROFIT Faster,Computer goes to Windows Boot Manager after Start,Connect to one of my network computer remotely when don't allow exception box Marked,computer locking up randomly